Interactive robots and home appliances are commercially available (for example, see NPD 1). Dialog has been known to heal fatigue (for example, see NPD 2). NPD 2 indicates that dialog with robot home appliances has the effect of reducing stress and effective especially for elderly people.
Dementia patients have been increasing among elderly people. There is an approach for dementia, called reminiscence therapy (for example, see NPDs 3 to 5). Reminiscence is a psychological therapy proposed by an American psychiatrist, Dr. Robert Butler. It is expected that bringing back memories in the past and sharing memories with someone else stimulates brain and stabilizes the mental state. Having the therapy for a long time has proven to improve the cognitive function, and the therapy has been utilized in rehabilitation of dementia patients also in Japan. In short, this approach allows patients to recall the past mainly through conversation with people and thereby improves the mental state. This approach is often used in therapy for cognition disorder of elderly people and sometimes used in treatment of depression.
Regarding the technique for improving dementia, Japanese Patent Laying-Open No. 2011-223369 (PTD 1) discloses “a conversation system for a patient with cognitive dementia that detects a smiling face of the patient with cognitive dementia and provides a suitable conversation corresponding thereto” (see [Abstract]). The technique disclosed in PTD 1 implements a system capable of selectively providing a conversation that attracts the patient's interest by counting the number of times a smiling face is detected according to a conversation data group in a dialog device for dementia patients.
Japanese Patent Laying-Open No. 2004-109323 (PTD 2) discloses “a voice interaction apparatus which can change spoken contents according to the state of interaction with a user as occasion may demand and realize intellectual and natural sound dialog” (see [Abstract]).